Lighting fixture



July 18, 1933. O PFE|FFER 1,918,823

LIGHTING FIXTURE Filed June 25, 1932 A TTORNEX Patented, July 18, 1933 RICHARD O. PFEII IFFER, OF SOUTH ORANGE, NEXV JERSEY LIGHTING FIXTURE a plication filed June 25,

be readily assembled and not readily or accidentally displaced, the improved fixture embodying features providing for maximum lighting etliciency and safety in each case.

Li 'htin fixture lass lobes are made oi?" a t: b t:

various depths and configurations, and the electric lamps enclosed within the lighting fixtures are also made of various sizes and configurations. In order to obtain maximum lighting efliciency in eachcase, it is essential that the lamp be so positioned within the globe that the lamp filament will give maximum lighting efficiency relatively to the globe. I

It is an object of my invention to provide means for vertically positioning the lamp within the glass globe so that the lamp will give maximum lighting efiiciency relatively to the globe in each case. A further object of my invention is to provide accessible lamp adjusting means referred to, which will not necessitate the disassembly of the fixture when repairs, inspection or the like are necessary.

A. further object of my invention is to provide a dustproof globe holder adapted to provide wide supporting surfaces for the globe and to rigidlyhold the globe, at the same time providing suliicient resiliency to prevent breaking of the globein' the event that the globe holder parts are excessively tightened or that the globe is subjected to undue stresses from any other cause.

These and other advantageous objects, which will later appear, are accomplished by the simple and practical construction and arrangement of parts hereinafter described and exhibited in the accompanying drawing, forming part hereof, and in which:

Fig. 1 represents a side elevational view of the lighting fixture embodying my invention,

Figs. 2 and 8 represent perspective views of the globe holding parts of the fixture,

'18. is suspended from the ceiling in any desired 1932. Serial No. 619,172.

Fig. 4 represents a perspective view, partly broken away, of the parts of my fixture from which the electric lamp is suspended, showing the adjusting means for vertically adjusting the position of the lamp, and

Fig. 5 represents a partly sectional plan view taken on lines 5-5 of Fig. 1.

My improved fixture as shown in the accompanying drawing preferably comprises an electric socket 11 having an upwardly eX- tendinghollow stem 12 WJlCll may be of square or any other-polygonalcross-section and freely slides in the opening 13 in the cap 16. The upper end of the stem 12 is flared outwardly as shown in Fig. 1 to provide holding means to prevent the stem from slipping through the opening 18 while the stem with the attached lamp 10 is adjusted so that the lamp will be vertically positioned to give maximumlighting etiiciency relatively to the globe 20 as will be presently more fully described. 7

After the stem with the attached lamp has been vertically adjusted to the desired point, itis secured in the cap 16 by means oii a set screw 15, in the tubular portion 1-1 of the cap. The cap 16, at its lower end, is

provided with an outwardly extending flange 14:, to which the upper end of the glob-e supporting inner shell 18 is secured in any desired or convenient manner, preferably by means of screws 52% which pass through suitable apertures in the inner shell 18 and have screw threaded engagement with the flange 1 1. $.11 outer shell 21 is passed over the elongated hollow tube 17 carrying the cap 1 1 for engagement with the inner shell The upper end of the hollow tube 17 or convenient manner. the electric wires pass- 111g from the electric socket through the hollow stem 12 and hollow tube 17 to an out- 7 let box (not shown) in the ceiling, in which ment of the stem, a maximum lighting efiiciency in each case may be attained.

After it has been determined what particular kind of electric lamp and what particular type of globe are to be employed in the particular fixture, the stem 12 is vertically adjusted so that when the lamp is positioned in the socket and the globe is placed in position, the lamp will give maximum lighting efiiciency relatively to the lobe. It will be noted that this adjustment is made from the outside without necessitating the disassembling of the fixture.

The neck portion of the inner shell 18 is relatively hard and is provided with enlarged threads and is further provided, at diametrically opposite points at its lower end, with laterally extending arms 19*19, the outer .iities of which are stepped and curved to form the arced shoulders 19 19 (see Fig. 3).

The inner shell-18 is made from a disc which is preferably machined so that the arms and shoulder portions thereof will posscss sufiicient rigidity to supportthe globe 20, and, at the same time be sufiiciently resilient to yield slightly upon the application of excessive pressure to the globe, due to excessive tightening of the shells 18 and 21 or to the application of force to the globe in any other manner, to prevent breaking of the globe. The arms and shoulder portions of the supporting shell 18 may be provided with weakening marginal slots 22 to make the same v ei-ltre even more resilient, if desired, for this purpose.

To position'the globe in the fixture, the globe is tilted at an angle so that one arm 19 of the globe supporting shell 18 enters the globe at an angle and then continuing at that angle, the globe is carried over the other arm 19 of the supporting shell '18 and then is moved to a horizontal position torest on the shoulder 1919, which support the same. The outer shell 21 is preferably formed from a disc and threadedly engages the inner shell 18 and overlapsthe top of the globe, immovably positioning the same between the shells 18 and 21, and making the fixture dustproof. It will be noted that after the assembling of the parts as set forth abovethe same cannot he accidentally displaced.

lVhile l have shown the fixture suspended by means of the tube 17 it is within the scope of my invention-to employ the essential fea tures described above in connectionwith a fixture suspended in any other manner such as by means of a canopy rigidly connected to the supporting shell 18, the canopy being provided with a slot through which access to the set screw may be had from the outside of the fixture without disassembling the same (not shown).

The arrangement described is applicable not only to ordinary lighting fixtures but also is adapted for use in medical work in hospitals and the like and for scientific use, Where minute and accurate adjustment of the position of an electric lamp filament relatively to a globe is desirable.

The stem 12 which is preferably of any desired or convenient non-circular form may be roughened at its outer surfaces to facilitate the action of the set screw 15.

The foregoing disclosure is to be regarded as descriptive and illustrative only, and not as restrictive or limitative of the invention, of which obviously an embodiment may be constructed including many modifications without departing from the general scope herein indicated and denoted in the appended claim.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

An electric lighting fixture comprising, a cap provided with an outwardly extending flange, and with a longitudinal keyway, an

.inner shell secured to the flange of said cap,

said inner shell being provided with oppositely disposed laterally extending arms, the outer extremities of which are stepped and curved to form arced shoulders, a globe provided with a neck portion resting on the shoulder portions of the inner shell, an outer shell threadedly engaging the inner shell, and overlapping the neck portion of the globe to rigidly secure the latter between the shells, the arm and shoulder portions of the inner shell being slightly resilient to prevent breaking of the globe upon application of cxcessive pressure or force thereto and to provide a dust-tight fit between the outer shell and globe, an electric lamp carrying stem positi oned in the cap keyway, and means passing through the cap and adapted to be brought into engagement with the stem to position the same in the keyway at the point at which the electric lamp will give maximum lighting efiiciency with reference to the type of globe used in the fixture.

RICHARD O. PFEIFFER. 

